The present invention relates to mobile RF terminals required to conduct bi-directional communications with a base station via a satellite link, and more particularly to a method and apparatus for quickly identifying which one of a plurality of mobile terminals is causing interference with one or more satellites orbiting in the vicinity of a target transponded satellite.
With mobile RF terminals located on mobile platforms such as aircraft, cruise ships and other moving platforms, communicating with a ground station via a transponded satellite, there is always the remote possibility, in spite of the safeguards that may be built into the mobile terminal, that the terminal may fail in an unanticipated manner. In such event, there is the possibility that the mobile terminal may cause interference with other satellites orbiting in the geo arc adjacent the target satellite with which the mobile terminal is communicating.
It is also recognized that Fixed Services Satellite (FSS) operators may have difficulty in locating interference from VSAT (Very Small Aperture Terminal) systems that consist of thousands of unsophisticated terminals at remote sites. This problem is compounded when the remote terminals comprise mobile terminals that are located on fast moving platforms, such as jet aircraft.
Therefore, there exists a need for the ground station in communication with a plurality of mobile terminals via a transponded satellite to be able to quickly identify a malfunctioning mobile terminal which is causing interference with non-target satellites and to quickly resolve the interference incident.
The present invention relates to a system and method for quickly determining which one of a plurality of mobile terminals communicating with a base station, such as a ground-based communication system or segment, is causing interference with one or more satellites adjacent a target transponded satellite. The system and method uses a network operations center (NOC) of the ground-based segment to command each mobile terminal of each aircraft utilizing the target transponded satellite to carry out a transmit lobing sequence, to thereby determine the off-axis effective isotropic radiated power (EIRP) of the signal transmitted by the transmit antenna of each mobile terminal.
The NOC uses the information obtained during the transmit lobing process to determine whether a parameter of the transmitted signals received by it during the transmit lobing process indicates that the mobile terminal is the cause of interference. If it is not, then the NOC performs the transmit lobing sequence with the mobile terminal of a second aircraft accessing the transponded target satellite, and thereafter with every mobile terminal accessing the transponded target satellite until the mobile terminal causing the interference is detected.